1. Field of the Invention
The present invention relates to a recording sheet/ink sheet integral cassette accommodating a recording sheet and an ink sheet, and a printer apparatus utilizing such cassette.
2. Description of the Related Art
Printer apparatuses utilized as an output device of a computer or an output device for a digital image can be classified, according to the recording method, into a thermal transfer printer apparatus, an ink jet printer apparatus, a laser printer apparatus, a wire dot printer apparatus and the like. Among these, a line thermal transfer printer apparatus utilizes an ink sheet and a recording sheet, and based on selectively driving plural heat-generating members arranged along a main scanning direction, while conveying the ink sheet and the recording sheet in a sub scanning direction, thereby forming a print in a dot-line shape on the recording sheet.
Along with the recent progress in the input devices for handling input images, such as a digital camera, a digital video camera, a scanner and the like, the thermal transfer printer apparatus is attracting increasing attention. The thermal transfer printer apparatus is suitable for forming an output print, through a computer or a recording medium, of electronic image information phototaken by a still camera or a video camera recording a still image.
As printer apparatuses of other printing methods such as an ink jet printer apparatus have only a binary selection whether or not to form a dot, and a resolution and a gradation are obtained in apparent manner by forming small dots on the recording sheet and utilizing an error diffusion method or the like. In contrast, in the thermal transfer printer apparatus, a heat amount for controlling a pixel can be changed easily, so that plural gradation levels can be obtained in one pixel. Therefore, such printer apparatus has an advantage of obtaining a smoother image of a higher image quality, in comparison with other printer apparatuses such as an ink jet printer apparatus.
Also the thermal transfer printer apparatus is capable, owing to improvements in the performance of a thermal head as the recording means and the performance of a recording sheet, of providing an image print comparable in quality to a silver halide photograph. Thus, as keeping up with the recent progress in digital cameras, the thermal transfer printer apparatus is attracting attention as a printer particularly for a natural image.
Also recently available is a system for direct print output of captured image information without going through a computer or the like, by directly connecting or integrally constructing the thermal transfer printer apparatus and an image capturing device such as a digital camera or a digital video camera. Such system enables easy photographic printout of image information from the digital camera or the digital video camera, thereby increasing the attention to the thermal transfer printer apparatus. In the thermal transfer system, however, inks of plural colors have to be repeatedly transferred in superposition in order to obtain a full-color print, and a general structure for realizing such transfer will be explained in the following.
A first example of a general structure of the prior thermal transfer printer is shown in FIGS. 32A and 32B. As shown in FIG. 32A, among the recording sheets stacked on a recording sheet cassette 107, an uppermost recording sheet only is separated and fed by a feeding roller 108 and separation means 109 and conveyed to a position between a thermal head 104 and a platen roller 105. A printing operation is executed by winding the recording sheet P on a periphery of the platen roller 105, having an external periphery somewhat longer than the entire length of the recording sheet P, by pressurizing an ink sheet 106 and the recording sheet P by the thermal head 104 and the platen roller 105, and by rotating the platen roller 105 while thermally transferring an ink of the ink sheet 106 onto the recording sheet P by a heat generated by the thermal head 104. Then, after the printing of the first color, in order to print with a next color, the pressurization by the thermal head 104 is released as shown in FIG. 32B, then the platen roller 105 is further rotated to advance the recording sheet P to a print start position, and the second and subsequent colors are printed in operations similar to that for the first color. A full-color printing is achieved by superposing three colors of yellow, magenta and cyan in this manner.
A second example of the general structure of the prior thermal transfer printer is shown in FIGS. 33A and 33B. As shown in FIG. 33A, among the recording sheet P stacked on a paper cassette 201, an uppermost recording sheet only is separated and fed by a feeding roller 202 and separation means 203 and conveyed toward a thermal head 204 and a platen roller 205. A printing operation is executed by pressurizing an ink sheet 206 and the recording sheet P by the thermal head 204 and the platen roller 205, and by conveying the recording sheet P by means of a capstan roller 207 and a pinch roller 208 in pair, provided in a downstream side in the printing direction while thermally transferring an ink of the ink sheet 206 onto the recording sheet P by a heat generated by the thermal head 204.
After the printing of the first color, a next color is printed. For this purpose, the pressurization by the thermal head 204 is released as shown in FIG. 33B, then the capstan roller 207 and the pinch roller 208 are rotated in a direction opposite to that in the printing operation to return the recording sheet P to a print start position, and the second and subsequent colors are printed in operations similar to that for the first color. A full-color printing is achieved by superposing three colors of yellow, magenta and cyan in this manner.
In the example shown in FIGS. 32A and 32B or that shown in FIGS. 33A and 33B, the recording sheet and the ink sheet in the paper cassette are consumables, and have to be replaced and replenished according to the use. The ink sheet is commonly supplied to the user in a cartridge of a structure in which both ends of an ink sheet are wound on two bobbins and in which such two bobbins and the ink sheet are accommodated in a frame member. A numeral 110 in FIGS. 32A and 32B and a numeral 210 in FIGS. 33A and 33B indicate a frame member of such cartridge. The cartridge has a cavity portion as indicated by 110a or 201a, and, in case of mounting the cartridge, it is guided and mounted in a predetermined position in such a manner that the thermal head 104 or 204, provided in a main body, becomes positioned in such cavity portion of the cartridge.
The two methods above have been used commonly. The first examples involves disadvantages of requiring a platen roller having an external periphery somewhat longer than the entire length of the recording sheet P, thus resulting in a bulky apparatus, and of requiring a mechanism, though not illustrated in FIGS. 32A and 32B, for winding and supporting the recording sheet on the periphery of the platen roller, thus complicating the apparatus. It however has an advantage of not requiring a time for returning the recording sheet as in the second example, since the print start position for the second color is located immediately after when the printing of the first color is completed thus achieving a higher printing speed. On the other hand, the second example involves a disadvantage that the printing time is extended, but has an advantage allowing compactification and simplification of the apparatus.
However, in the thermal transfer printer apparatus described above, in order to obtain a satisfactory print, an exclusive paper having a surface capable of receiving easy transfer of the ink has to be used as the recording sheet. Therefore, an ink cartridge containing an ink sheet corresponding to 50 recording sheets and 50 recording sheets are sold as a set. In the use of the printer, the user is required to go through a trouble of opening a package of the recording sheets and the ink cartridge, sold in a set, and respectively mounting the ink cartridge in the main body and the recording sheets in the paper cassette.
In the thermal transfer printer, a loss in the ink sheet can be reduced by preparing different ink sheets respectively corresponding to the recording sheet sizes as shown in FIG. 34. Therefore, as shown in FIG. 34, for example recording sheets of A6 size and an ink cartridge containing an ink sheet for A6 size are sold as a set, and recording sheets of A7 size and an ink cartridge containing an ink sheet for A7 size are sold as a set. The user purchases these sets according to its purpose, and, in case of executing a printing of A7 size after a printing of A6 size, the user has to remove the A6-sized recording sheets and the ink cartridge for A6 size, and to instead mount the A7-sized recording sheets and the ink cartridge for A7 size.
The A6-sized recording sheets and the ink cartridge for A6 size, removed in this case, have to be stored for a later use. As the ink cartridge and the recording sheets are separate and have to be kept away from dusts and direct sunlight, there is involved a trouble of storing these in a storage bag or the like. In order to avoid these troubles, there is proposed a cartridge integrally containing the ink sheet and the recording sheets as disclosed in Japanese Patent No. 2523355, and Japanese Patent Application Laid-open No. 2000-108442.
However, the cartridge of Japanese Patent No. 2523355, though integrating an ink sheet containing portion and a recording sheet containing portion, has such a structure incapable of executing a printing operation in a state where the ink sheet is accommodated in the cartridge. In order to executing a printing operation, there is required a mechanism of taking out the ink sheet from the cartridge and loading it to a printing position, and such mechanism involves a drawback of complicating the apparatus and lowering the reliability.
Japanese Patent Application Laid-open No. 2000-108442 proposes an improvement over the drawback of Japanese Patent No. 2523355. In this proposal, the integral cartridge, after being mounted, is capable of executing a printing operation with the ink sheet not loaded to the printing position but in the mounted position. It is thus so structured that the user does not feel the trouble of mounting the ink sheet and the recording sheets separately in the printer apparatus and, in case of using the recording sheet of different types, of removed ink sheet and recording sheets separately.
However, in the case that a photographic printing is a prime object, the paper to be used requires a certain thickness in order to secure a storability, a durability and a print quality. Therefore, a extreme bending of the paper during the conveyance for printing may cause a damage or creases on a printing surface. Also in a case where the recording sheet has a large thickness, the reliability of separation of the recording sheet from the cassette may be lowered, depending on the separating method, unless a space for sufficiently bending the recording sheet is made available.
In Japanese Patent Application Laid-open No. 2000-108442, a conveying path for the paper is formed in the cassette, and the external shape thereof is formed with an arc of a certain large radius R in order to avoid an extreme bending, for suppressing the damage to the paper and improving the reliability in conveyance. However the interior of such R-shape, for forming the conveying path, forms a wasted space. Also in order to obtain a smooth bending in the conveying path, the cassette requires a certain size in the thickness direction, and gives a limit in the compactification. As a result, the cassette exceeds the minimum necessary size required for containing the ink sheet of the papers, and leads to a bulkiness of the main body of the printer.